Date/Time: February 5th (Wednesday) noon

Where: Center for Atmospheric Sciences Class Room (Phenix 123)

Speaker: William Moore

From: Atmospheric and Planetary Sciences Department, Hampton University

Topic: Planetary Cooling From Magma Oceans to Heat Pipes to Plate Tectonics

Abstract:

The fundamental role of volcanism as a global heat and mass transport process on the terrestrial planets has largely been overlooked, since these effects are minor at present everywhere but Jupiter’s moon Io. Nonetheless, the endogenic resurfacing of all terrestrial bodies other than Earth is dominated by volcanic landforms. When volcanism dominates heat transport, a terrestrial body enters a heat-pipe mode, in which hot magma moves through the lithosphere in narrow channels. Even at high heat flow, a heat-pipe planet develops a thick, cold, downwards-advecting lithosphere dominated by (ultra-)mafic flows and contractional deformation at the surface. Early geologic evolution of each terrestrial body in the Solar System is consistent with heat-pipe cooling. These planets subsequently transitioned into a rigid-lid convective phase or a plate-tectonic phase, depending on the interaction between stresses in the mantle and the strength of the lithosphere. Heat-pipe cooling is a universal process experienced by all terrestrial bodies of sufficient size. Terrestrial exoplanets appreciably larger than Earth may remain in heat-pipe mode as long as a typical star lifespan.